Design of a Split-Ring Resonator Sensor for Near-Field Microwave Imaging

Metamaterials have been increasingly used in the past few decades in the design of novel microwave circuits and sensor systems. This paper deals with the design of a split-ring resonator (SRR) sensor for microwave nondestructive evaluation (NDE) applications. Building on prior work in this field, a modified design of the sensor is used for imaging composites. The tip of the sensing ring is extended, and a reference ring is introduced to tailor fit the sensor for imaging and NDE applications. A built-in calibration system, integration of multiple sensors (high and low frequencies), super resolution capability, and high-Q factor are some of the benefits of the sensor. This paper presents the design and development of the sensor system along with experimental results demonstrating the feasibility of the approach for detection of sub-wavelength defects in composites and additive manufactured metals.